The present invention pertains generally to hook assemblies interposed between a source of lifting force such as a crane, helicopter, etc., and a load to be lifted.
In the transport of consecutive loads by helicopters it is important, for operating cost purposes, to fully utilize the load lift capability on each flight where several flights are made in a work day. In the use of helicopters for transporting logs to a collection site, it is the practice to estimate log weight to fully utilize the lift capability of the helicopter. As estimating log weight is an imprecise matter, it can occur that a log load or bundle of logs will exceed the aircraft's limits in which case the load must be altered all at the loss of productive flight time. The other extreme to be avoided is the transport of light loads far below lift capability which also results in a high cost per log transported.
U.S. Pat. No. 5,040,748 discloses the use of multiple toggle assemblies which cooperate to retain a load attached pin in place on a ring which carries other toggle assemblies for attachment of other independently released loads on the ring. U.S. Pat. No. 2,986,421 shows the use of air cylinders mounted in inclined relationships to the longitudinal axis of a hook assembly.